Common and Uncommon Imaging Manifestations of Thoracic and Disseminated Coccidioidomycosis Infection

Coccidioidomycosis is caused by the dimorphic fungus <i>Coccidioides</i>, endemic to the southwestern United States. Most infected patients are asymptomatic or recover uneventfully, but a small proportion will develop chronic infection or dissemination. Diagnosis typically rests on organism demonstration in tissue or serology, but knowledge of <i>Coccidioides</i> infection imaging findings becomes important when tissue examination is not possible and serologic results are unclear. Acute coccidioidal pneumonia manifests at chest imaging with consolidation and lymphadenopathy, resolving completely or evolving into a nodule or cavity. Chronic coccidioidomycosis manifests with nodules or cavities that may persist. Uncommon coccidioidomycosis manifestations may simulate malignancy, including nodular pleural effusions, extrathoracic dissemination, and osseous disease. Thoracic coccidioidomycosis complications include pleural space cavity rupture causing bronchopleural fistula, cavity enlargement necessitating surgical intervention, and development of superinfection. Disseminated coccidioidomycosis affects the skin, central nervous system, and musculoskeletal system. Central nervous system coccidioidomycosis often manifests with basilar meningitis, with or without spinal leptomeningeal disease. Paraspinous fluid collections and discitis/vertebral body osteomyelitis simulating pyogenic infection occur, sometimes with relative disc space narrowing and slow disease progression. Musculoskeletal coccidioidomycosis manifests with lytic bone lesions and may produce peripherally enhancing fluid collections. Gastrointestinal coccidioidomycosis is uncommon, manifesting as peritonitis of unclear cause or peritoneal abscesses, rarely with solid organ low-attenuation lesions. Genitourinary coccidioidomycosis manifests as pyelonephritis or pelvic abscesses. Disseminated coccidioidomycosis diagnosis is facilitated through recognition of the common clinical context of immunocompromise coupled with travel to, or residence within, an endemic area. <b>Keywords:</b> Thorax, Lung, Mediastinum, Pleura, Tracheobronchial Tree, Fungus, Coccidioidomycosis, Spherules, Cavity, Nodule, Endemic, Dissemination <i>Supplemental material is available for this article.</i> © RSNA, 2025.